The Dons have slipped to 11th place in League Two after picking up just one point from their last three matches and now face tough trips to high-flying Morecambe and in-form Hartlepool.
Defender Fuller said: "We have to show character now. We do not want to get stuck in a rut. No matter how good a team you are it is hard to get out of it when you are losing games. We have to find that consistency again.
"We have difficult away games coming up but when the going gets tough you have to prove that you are up for the challenge. It may not be pretty but we have to roll our sleeves up.
"I have only been at the club for a short space of time but I feel that we can progress. I felt in pre-season we could be pushing for a place in the top half and I still feel exactly the same."